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authorRafał Miłecki <rafal@milecki.pl>2017-03-22 21:09:00 +0100
committerRafał Miłecki <rafal@milecki.pl>2017-03-24 08:06:35 +0100
commitfce21ae4ccfcee0c28fb18f5507e145fb0b02dec (patch)
tree6c29b7c1f65945991d0cae13af012e6c14adc713 /target/linux/brcm2708/patches-4.9/950-0106-i2c-bcm2835-Fix-hang-for-writing-messages-larger-tha.patch
parent46e390322a58bdc632ee43fdf9d14115dac26e7a (diff)
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brcm2708: rename all patches from raspberrypi git tree to use 950 prefix
Right now all brcm2708 patches are extracted from the non-mainline raspberrypi/linux git tree. Many of them are hacks and/or are unneeded in LEDE. Raspberry Pi is getting better and better mainline support so it would be nice to finally start maintaining patches in a cleaner way: 1) Backport patches accepted in upstream tree 2) Start using upstream drivers 3) Pick only these patches that are needed for more complete support Handling above tasks requires grouping patches - ideally using the same prefixes as generic ones. It means we should rename existing patches to use some high prefix. This will allow e.g. use 0xx for backported code. Signed-off-by: Rafał Miłecki <rafal@milecki.pl> Acked-by: Florian Fainelli <f.fainelli@gmail.com> Acked-by: Stijn Tintel <stijn@linux-ipv6.be>
Diffstat (limited to 'target/linux/brcm2708/patches-4.9/950-0106-i2c-bcm2835-Fix-hang-for-writing-messages-larger-tha.patch')
-rw-r--r--target/linux/brcm2708/patches-4.9/950-0106-i2c-bcm2835-Fix-hang-for-writing-messages-larger-tha.patch90
1 files changed, 90 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.9/950-0106-i2c-bcm2835-Fix-hang-for-writing-messages-larger-tha.patch b/target/linux/brcm2708/patches-4.9/950-0106-i2c-bcm2835-Fix-hang-for-writing-messages-larger-tha.patch
new file mode 100644
index 0000000000..899c75e0db
--- /dev/null
+++ b/target/linux/brcm2708/patches-4.9/950-0106-i2c-bcm2835-Fix-hang-for-writing-messages-larger-tha.patch
@@ -0,0 +1,90 @@
+From 89b466914a0d49f08d00be25556ba22497b9a284 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= <noralf@tronnes.org>
+Date: Sat, 17 Sep 2016 15:07:10 +0200
+Subject: [PATCH] i2c: bcm2835: Fix hang for writing messages larger than 16
+ bytes
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Writing messages larger than the FIFO size results in a hang, rendering
+the machine unusable. This is because the RXD status flag is set on the
+first interrupt which results in bcm2835_drain_rxfifo() stealing bytes
+from the buffer. The controller continues to trigger interrupts waiting
+for the missing bytes, but bcm2835_fill_txfifo() has none to give.
+In this situation wait_for_completion_timeout() apparently is unable to
+stop the madness.
+
+The BCM2835 ARM Peripherals datasheet has this to say about the flags:
+ TXD: is set when the FIFO has space for at least one byte of data.
+ RXD: is set when the FIFO contains at least one byte of data.
+ TXW: is set during a write transfer and the FIFO is less than full.
+ RXR: is set during a read transfer and the FIFO is or more full.
+
+Implementing the logic from the downstream i2c-bcm2708 driver solved
+the hang problem.
+
+Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
+Reviewed-by: Eric Anholt <eric@anholt.net>
+Reviewed-by: Martin Sperl <kernel@martin.sperl.org>
+---
+ drivers/i2c/busses/i2c-bcm2835.c | 22 ++++++++++++++--------
+ 1 file changed, 14 insertions(+), 8 deletions(-)
+
+--- a/drivers/i2c/busses/i2c-bcm2835.c
++++ b/drivers/i2c/busses/i2c-bcm2835.c
+@@ -64,6 +64,7 @@ struct bcm2835_i2c_dev {
+ int irq;
+ struct i2c_adapter adapter;
+ struct completion completion;
++ struct i2c_msg *curr_msg;
+ u32 msg_err;
+ u8 *msg_buf;
+ size_t msg_buf_remaining;
+@@ -126,14 +127,13 @@ static irqreturn_t bcm2835_i2c_isr(int t
+ return IRQ_HANDLED;
+ }
+
+- if (val & BCM2835_I2C_S_RXD) {
+- bcm2835_drain_rxfifo(i2c_dev);
+- if (!(val & BCM2835_I2C_S_DONE))
+- return IRQ_HANDLED;
+- }
+-
+ if (val & BCM2835_I2C_S_DONE) {
+- if (i2c_dev->msg_buf_remaining)
++ if (i2c_dev->curr_msg->flags & I2C_M_RD) {
++ bcm2835_drain_rxfifo(i2c_dev);
++ val = bcm2835_i2c_readl(i2c_dev, BCM2835_I2C_S);
++ }
++
++ if ((val & BCM2835_I2C_S_RXD) || i2c_dev->msg_buf_remaining)
+ i2c_dev->msg_err = BCM2835_I2C_S_LEN;
+ else
+ i2c_dev->msg_err = 0;
+@@ -141,11 +141,16 @@ static irqreturn_t bcm2835_i2c_isr(int t
+ return IRQ_HANDLED;
+ }
+
+- if (val & BCM2835_I2C_S_TXD) {
++ if (val & BCM2835_I2C_S_TXW) {
+ bcm2835_fill_txfifo(i2c_dev);
+ return IRQ_HANDLED;
+ }
+
++ if (val & BCM2835_I2C_S_RXR) {
++ bcm2835_drain_rxfifo(i2c_dev);
++ return IRQ_HANDLED;
++ }
++
+ return IRQ_NONE;
+ }
+
+@@ -155,6 +160,7 @@ static int bcm2835_i2c_xfer_msg(struct b
+ u32 c;
+ unsigned long time_left;
+
++ i2c_dev->curr_msg = msg;
+ i2c_dev->msg_buf = msg->buf;
+ i2c_dev->msg_buf_remaining = msg->len;
+ reinit_completion(&i2c_dev->completion);